The present invention relates to a new box for containing various products which have to be air tight preserved during a more or less long time, said box being inviolably secured up to when the products contained therein are used.
The invention is extended in particular to manufacturing of boxes which can contain products which have to be preserved a long time, such boxes being up to now made of metal.
The prior art has made available a plurality of embodiments of boxes comprising a body covered by a lid fixed either by soldering or by crimping, or still by a combination of these two means, weaker resistance areas being provided either at the upper part of the box or in the lid for enabling to tear-off either the box or the lid and to have access to the products contained in the box.
U.S. Pat. No. 2,941,660 relates to a container having a cover capable of being permanently sealed subsequent to a merchandise-filling operation and further capable of being easily severed or separated by the consumer for further functioning as a container and a sealably detachable cover therefor. The container is preferably made of thermoplastic type material.
French Patent No. 78-32472 relates to a container made of plastics material and provided with a cover also of plastics material and sealed to the container preferably by vibrations, particularly ultra-sonic vibrations. A breakable portion is provided preferably in the container near the top portion thereof. Breakage of the breakable portion provides the cover with a ring shaped portion which may be fitted on the remaining portion of the container and thus constitute a removable cover.
U.S. Pat. No. 3,463,347 describes a closure normally for use in combination with the conventional can, said closure comprising an end closure member adapted to be crimped with the flared can body to form a flange and thereby seal the end of the can, said closure having an annular groove in the underside thereof in proximity to said flange, cutting means received in said groove, said cutting means having an upstanding cutting edge, said cutting means also having a portion thereof projecting through said closure, a torsion bar carried diametrically on the outer side of said closure and being secured to a portion of said cutting means extending through said closure.
French Patent No. 1,335,350 describes a container having a groove opening on the top thereof and containing an annular blade intended to cut a cover which is sealed onto the container.
French Patent No. 1,511,724 is concerned with a container in plastics material having a portion of its lateral wall which is resilient and which is further provided with bellow portions for compensation of temperature differences.
The present invention provides a new box of a very low manufacturing cost which may be sterilized and vacuum filled, and which is then easy to open without necessitating any tooling, without the user of the box being possibly hurt, the box having moreover the advantage of being re-usable.
The present invention concerns improvements which obviate the risk to form a too large or too thin soldered area and, moreover, the opening of the box is made extremely easy.